KR20130036372A - System and method for synchronization tracking in an in-band modem - Google Patents

Abstract

Processing synchronization of the in-band modem to detect sample missing situations is disclosed. The process involves correlation of pseudorandom sequences. Decision logic reliably detects sample miss situations while minimizing the number of false alarms.

Description

SYSTEM AND METHOD FOR SYNCHRONIZATION TRACKING IN AN IN-BAND MODEM

Ⅰ. Priority claim

US Provisional Application, entitled “SYSTEM AND METHOD FOR SYNCHRONIZATION TRACKING IN AN IN-BAND MODEM”, filed Jul. 28, 2010, assigned to the assignee of the present application and expressly incorporated herein by reference. 61 / 368,624 claim priority.

Ⅱ. See ongoing patent application

The ongoing US patent applications involved are:

12 / 477,544, filed June 3, 2009, assigned to the assignee of the present application, entitled "SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS".

12 / 477,561, filed June 3, 2009, assigned to the assignee of the present application, entitled "SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS".

No. 1, filed on June 3, 2009, assigned to the assignee of the present application, entitled "SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS". 12 / 477,574.

12 / 477,590, filed June 3, 2009, assigned to the assignee of the present application, entitled “SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS”.

12 / 477,608, filed June 3, 2009, assigned to the assignee of the present application, entitled "SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS".

12 / 477,626, filed June 3, 2009, assigned to the assignee of the present application, entitled “SYSTEM AND METHOD OF AN IN-BAND MODEM FOR DATA COMMUNICATIONS OVER DIGITAL WIRELESS COMMUNICATION NETWORKS”.

12 / 816,197, filed June 15, 2010, assigned to the assignee of the present application, entitled “SYSTEM AND METHOD FOR SUPPORTING HIGHER-LAYER PROTOCOL MESSAGING IN AN IN-BAND MODEM”.

12 / 816,252, filed June 15, 2010 and assigned to the assignee herein, entitled " SYSTEM AND METHOD FOR SUPPORTING HIGHER-LAYER, PROTOCOL MESSAGING IN AN IN-BAND MODEM. &Quot;

Field of technology

In general, the present disclosure relates to data transmission over a voice channel. More specifically, the present disclosure relates to systems and methods that support sync tracking via a (in-band) speech codec in a communication network.

Since the advent of fixed line telephones and cordless telephones, voice transmission has been central to communication systems. Advances in communications system research and design have shifted the industry to digital based systems. One advantage of digital communication systems is the ability to reduce the required transmission bandwidth by implementing compression on the data to be transmitted. As a result, much research and development has been done in compression technologies, especially in the field of speech coding. Common speech compression devices are "vocoder" and are also interchangeably called "voice codec" or "voice coder". The vocoder receives the digitized speech samples and produces sets of data bits known as "voice packets". In the support of different digital communication systems requiring voice communication, there are several standardized vocoding algorithms, and in fact, voice support is the minimum and basic requirement in most communication systems today. 3rd Generation Partnership Project 2 (3GPP2) specifies IS-95, CDMA2000 1xRTT (1x wireless transmission technology), CDMA2000 Evolution-Data Optimized (EV-DO), and CDMA2000 Evolution-Data / Voice (EV-DV) communication systems. An exemplary standardization body. Third Generation Partnership Project (3GPP) includes Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), High-Speed Downlink Packet Access (HSDPA), and High Speed Uplink Packet Access ( Other exemplary standardization bodies specifying High-Speed Uplink Packet Access (HSUPA), High-Speed Packet Access Evolution (HSPA +), and Long Term Evolution (LTE). Voice over Internet Protocol (VoIP) is an exemplary protocol used in communication systems, defined as well as 3GPP and 3GPP2, as well as elsewhere. Examples of vocoders and protocols used in such communication systems include ITU-T G.729 (International Telecommunications Union), Adaptive Multi-rate Speech Codec (AMR), And Enhanced Variable Rate Codec (EVRC) Speech Service Options 3, 68, 70.

In support of the need for immediate connectivity and ubiquitous connectivity, information sharing is the main purpose of today's communication systems. Users of today's communication systems transmit voice, video, text messages, and other data and stay connected. New applications developed tend to lead the evolution of networks and may require upgrades to communication system modulation techniques and protocols. In some remote geographic regions, only voice services may be available due to lack of infrastructure support for advanced data services in the system. Otherwise, users may choose to enable only voice services on their communication device for economic reasons. In some countries, support of public services such as Emergency 911 (E911) or eCall is required in the communication network. In such emergency applications, fast data transfer is a priority, but not always feasible, especially when advanced data services are not available at the user terminal. Previous techniques have provided solutions for transmitting data via the speech codec, but these solutions, due to coding inefficiencies incurred when attempting to encode a non-speech signal with a vocoder, only low data rate transmissions. Can support

Usually, transmitting data over a voice channel is called "in-band" data transmission, where the data is contained in one or more voice packets output from the voice codec. Several techniques use audio tones at predetermined frequencies within a voice frequency band to represent data. Using voice frequency codecs, in particular using predetermined frequency tones to transmit data at higher data rates, is unreliable due to the vocoders used in the systems. Vocoders are designed to model speech signals using a limited number of parameters. Limited parameters are insufficient to effectively model tonal signals. When attempting to increase the transmission data rate by quickly changing the tones, the performance of the vocoders modeling the tones is further degraded. This affects the detection accuracy, leading to the need to add complex techniques to minimize data errors, which in turn further reduces the overall data rate of the communication system. Therefore, there is a need for efficient and effective transmission of data through voice codecs in communication systems.

An efficient in-band modem is described in detail in US patent application Ser. No. 12 / 477,544, assigned to the assignee herein. In-band modems send information, such as emergency information in an eCall application, from source to destination and, at the destination, send a lower layer acknowledgment at the in-band modem layer to indicate proper receipt of the transmitted information. To allow.

An in-band modem with a higher layer acknowledgment protocol is described in detail in US patent application Ser. No. 12 / 816,252.

For example, in cases where the destination communication terminal is connected to an analog line that implements re-sampling, or otherwise, a phenomenon known as sample slip, due to drift between two different clock sources. This may happen between the source and destination communication terminals. This can potentially cause loss of synchronization in the in-band modem. Other potential causes of sample dropout may include buffer overrun or underrun situations that may be caused by system handoff, or implementations of jitter buffers.

Accordingly, it would be advantageous to provide an improved system for communicating over a voice channel that supports sync tracking.

Embodiments disclosed herein address the above mentioned needs by synchronously tracking sample slip situations in an in-band modem.

In one embodiment, a method for identifying missing samples in a transmission channel of an in-band modem includes receiving a synchronization sequence, correlating the received synchronization sequence with a reference signal, and repeating pseudo if synchronization is locked at the receiver. Calculating a plurality of correlation peaks based on the random sequence; And identifying a sample miss based on the correlation peaks.

In another embodiment, a method of identifying sample missing in a transmission channel of an in-band modem includes receiving data bits, correlating received data bits with a reference signal, and identifying sample missing based on correlation. Steps.

Aspects and accompanying advantages of the embodiments described herein, when taken in conjunction with the accompanying drawings, will become more readily apparent by reference to the following detailed description, wherein:
1 is a diagram of one embodiment of a telematics emergency call system.
2 is a diagram of one embodiment of a source terminal and a destination terminal using an in-band modem to transmit messages via a voice codec in a wireless communication network.
3A is a diagram of an embodiment of a source terminal interfaced to a sound card via an analog interface.
3B is a diagram of an embodiment of a destination terminal interfaced to a sound card via an analog interface.
4 is a diagram of one embodiment of the timing of a first clock source.
5 is a diagram of one embodiment of the timing of a second clock source that has a higher frequency than the first clock source, resulting in a sample missing (additional pulse) situation.
6A is a diagram of an embodiment of the timing of a second clock source having a lower frequency than the first clock source.
FIG. 6B is a diagram of an embodiment of the timing of a second clock source that has a frequency lower than the first clock source and drifts over time with respect to the first clock source.
FIG. 6C illustrates an embodiment of the timing of a second clock source having a lower frequency than the first clock source and drift to any point in time with respect to the first clock source resulting in a sample missing (lost pulse) situation. It is a diagram.
7 is a diagram of an embodiment of the interaction of a data request sequence sent on the downlink at the destination communication terminal and a data response sequence sent on the uplink at the source communication terminal with the interaction initiated by the destination terminal. Here, the downlink transmission consists of a lower layer acknowledgment message and a higher layer application message, and the uplink transmission ends based on the higher layer application message.
8A is a diagram of an embodiment for a synchronous preamble sequence.
8B is a graph of output synchronous preamble correlation.
9A is a diagram of a second embodiment of a synchronous preamble sequence.
9B is a graph of the correlation output for the second embodiment of the synchronous preamble sequence.
FIG. 10A is an exemplary graph of the correlation output for the first peak of the synchronous preamble sequence of FIG. 8A. FIG.
FIG. 10B is an exemplary graph of the correlation output for the second peak of the synchronous preamble sequence of FIG. 8A.
FIG. 10C is an exemplary graph of the correlation output for the third peak of the synchronous preamble sequence of FIG. 8A.
FIG. 10D is an exemplary graph of the correlation output for the fourth peak of the synchronous preamble sequence of FIG. 8A.
FIG. 10E is an exemplary graph of the correlation output for the fifth peak of the synchronous preamble sequence of FIG. 8A.
FIG. 10F is a graph of correlation output of a reference pulse consisting of a scaled sum of five peaks of the synchronous preamble sequence of FIG. 8A.
11A is a flowchart for preparation for downlink sample miss detection.
11B is a flowchart of a method M100 for preparing for downlink sample drop detection.
11C is a flowchart for the first set of means of apparatus A100 according to the first configuration of preparation for downlink sample miss detection.
12 is a diagram of an embodiment of a transmit data modem used in an in-band communication system.
FIG. 13 is a diagram of an embodiment of a transmit data message format including compound synchronization and a first duplicated version, a second duplicated version, and a third duplicated version. FIG.
14A illustrates the interaction of a data request sequence sent on the downlink at the destination communication terminal with a data response sequence sent on the uplink at the source communication terminal with mute, synchronization, and data including respective duplicate versions. A diagram of one embodiment.
14B illustrates the interaction of a data request sequence sent on the downlink at the destination communication terminal and a data response sequence sent on the uplink at the source communication terminal with data including mute, synchronization, and respective duplicate versions. A diagram of another embodiment.
14C illustrates the interaction of a data request sequence sent on the downlink at the destination communication terminal with a data response sequence sent on the uplink at the source communication terminal with mute, synchronization, and data including respective duplicate versions. It is a diagram of another embodiment.
15 is a diagram of an embodiment of a sparse pulse data symbol representation.
16A is a flowchart of an uplink synchronous demodulator.
16B is a flowchart of the first correlation calculation for the uplink synchronous demodulator.
16C is a flowchart of the second correlation calculation for the uplink synchronous demodulator.
16D is a flowchart of a method M200 of an uplink synchronous demodulator.
16E is a flowchart for a first set of means of apparatus A200 according to the first configuration of an uplink synchronous demodulator.
17A is a diagram of one embodiment of a comb pulse.
17B is a diagram of another embodiment of a comb pulse.
18A is a diagram of a series of comb pulses formed with a length of 15 PN by weighting sequence indices 0 through 7.
18B is a diagram of a series of comb pulses formed with a length of 15 PN by weighting sequence indices 8 to 14.
19A is a block diagram of one implementation of an apparatus according to a first configuration.
19B is a block diagram of an implementation of an apparatus according to the second configuration.

Unless expressly limited by context, herein, the term “signal” means its original meaning, including the state of a memory location (or set of memory locations) as represented on a wire, bus, or other transmission medium. Used to indicate any of these meanings. Unless specifically limited by context, the term “generating” is used herein to refer to any of its original meanings, such as producing or otherwise producing. Unless expressly limited by context, herein, the term “compute” is used to denote any of its original meanings such as calculating, evaluating, estimating, and / or selecting from a plurality of values. Used. Unless specifically limited by context, the term “get” refers to such things as calculating, deriving, receiving (eg, from an external device), and / or retrieving (from arrays of storage elements). Used to indicate any of the original meanings. Unless expressly limited by context, the term “choice” is any of its original meanings such as identifying, indicating, applying, and / or using at least one of two or more sets and less than all of the two or more sets. It is used to indicate the meaning of. The term “comprising” is used in this specification and claims, which do not exclude other elements or operations. The term "based on" (as in "A is based on B") means (i) "derived from" (eg, "B is a precursor of A"), (ii) "at least Based on "(eg," A is based on at least B), and (iii) "equal to" (eg, "A is equal to" B ") if appropriate in a particular context. Are used to indicate any of its original meanings, and similarly, the term "in response to" includes any of its original meanings, including "at least in response to". Used to indicate meaning.

Unless indicated otherwise, any disclosure of the operation of a device having a particular feature also expressly seeks to disclose a method with similar features (and vice versa), and to operate the device according to a particular configuration. Any disclosure to is also clearly intended to disclose a method according to a similar configuration (and vice versa). The term “configuration” may be used in connection with a method, apparatus, and / or system as indicated by the specific context. The terms "method", "process", "procedure", and "technology" are used generally and interchangeably unless indicated by the specific context. Also, the terms “apparatus” and “device” are used generally and interchangeably unless otherwise indicated by the specific context. In general, the terms “element” and “module” are used to refer to a portion of a larger configuration. Unless expressly limited by context, the term “system” herein refers to any of its original meanings, including a group of elements that interact to serve a common purpose. In addition, any arbitrary inclusion as a reference in a part of a document should be understood to include definitions of terms or variables referred to within that part, where such definitions are included in this document as well as in the included parts. It is shown in any of the figures referenced elsewhere in.

In a typical application, a system, method, or apparatus is used to control transmissions from a source terminal or destination terminal in an in-band communication system. The system, method, or apparatus may include protocols for transmitting and receiving data between a source terminal and a destination terminal. The protocols may include signals for synchronizing data transmitted between the source terminal and the destination terminal. Signals may not synchronize data properly due to differences in sampling timing (eg, caused by different clock mechanisms, handoff between cell base stations, or jitter buffer control) between a source terminal and a destination terminal. This may cause additional sample or lost samples, and / or incorrect sample index for a predetermined amount (eg, frame) of data. Otherwise, the signals may initially synchronize data correctly, but after some time synchronization may be lost. The system, method, or apparatus may be used to enhance and / or detect and track synchronization signals.

1 represents a general example of an emergency call (eCall) system. Vehicle accident 950 is shown as a traffic accident between two vehicles. Other suitable examples for vehicle accident 950 include a multi-vehicle accident, a single vehicle accident, a flat tire of a single vehicle, a single vehicle engine malfunction, or a vehicle malfunction or other case in which the user needs assistance. In-Vehicle System (IVS) 951 may be located in one or more vehicles involved in a vehicle accident 950 or may be located in the user himself. The in-vehicle system 951 may be configured with a source terminal and a destination terminal. In-vehicle system 951 communicates over a wireless channel, which may be comprised of uplink communication channel 501 and downlink communication channel 502. The request for data transmission may be received by the in-vehicle system via a communication channel, or may be generated automatically or manually in the in-vehicle system. A wireless tower 955 receives the transmission from the in-vehicle system 951 and interfaces with a wired network consisting of a wired uplink 962 and a wired downlink 961. A suitable example of a wireless tower 955 is a cellular telephone composed of antennas, transceivers, and backhaul equipment, both well known in the art, for interfacing to wireless uplink 501 and downlink 502. Communication tower. The wired network interfaces to a Public Safety Answering Point (PSAP) 960 where emergency information sent by the in-vehicle system 951 may be received and control and data may be transmitted. Alternatively, the PSAP 960 may eliminate the wired network interface and integrate into a Mobile Switching Center. The public safety response point 960 may be configured with the destination terminal 600 described herein. Communication between the in-vehicle system 951 and the public safety response point 960 may be accomplished by transmitting and receiving protocols including synchronization enhancement and / or tracking techniques. In addition, other suitable examples for vehicle accident 950 may include vehicle inspection, maintenance, diagnostics, or other cases in which in-band data transmission from the vehicle may occur. In this case, the public safety response point (PSAP) 960 may be replaced by the destination terminal server.

2 illustrates one embodiment of an in-band data communication system that may be implemented within a wireless source terminal 100. The input data S200 is processed by the transmission baseband 200 and output as the transmission baseband data S201. Processing of the transmit baseband 200 may include message formatting, modulation, and vocoder encoding. The input data S200 may include user interface (UI) information, user location / location information, time stamps, equipment sensor information, or other suitable data. Transmit baseband data S201 is input to transmitter 295 and antenna 296 and transmitted via communication channel 501. Data is received via the communication channel 502 by the receiver 495 and output as received baseband data S401. The received baseband data S401 is input to the received baseband 400, processed and output as the output data S300 and the output audio S310. Processing of the receive baseband 400 may include vocoder decoding, timing recovery, demodulation, message deformatting, and synchronization detection and control. Source terminal 100 communicates with destination terminal 600 via communication channels 501 and 502, network 500, and communication channel 503. Examples of suitable wireless communication systems include Global Mobile Communication System (GSM), Third Generation Partnership Project Universal Mobile Communication System (3GPPUMTS), Third Generation Partnership Project 2 Code Division Multiple Access (3GPP2CDMA), Time Division Interlocking Code Division Multiple Access (Time) Division Synchronous Code Division Multiple Access (TD-SCDMA), and cellular telephony systems operating in accordance with Worldwide Interoperability for Microwave Access (WiMAX) standards. Those skilled in the art will appreciate that the techniques described herein may equally apply to in-band data communication systems that do not include a wireless channel. The communication network 500 includes any combination of routing and / or switching equipment, communication links, and other infrastructure suitable for establishing a communication link between the source terminal 100 and the destination terminal 600. For example, communication channel 503 may not be a wireless link. Normally, source terminal 100 functions as a voice communication device.

FIG. 3A shows an exemplary configuration illustrating separate sample clock mechanisms between source terminal 100 and source card 300, where audio input signal S210 and audio output signal S310 are analog interfaces. Interface to the sound card 300. The ST clock 101 is a clock generator at the source terminal 100 and may be used, for example, to drive the sample rate of the analog to digital converter for the audio signal S210. SC clock 301 is a clock generator in sound card 300 that is separate from source terminal 100 and may likewise be used to drive the sample rate of an analog to digital converter. 3B shows a similar configuration for destination terminal 600, where DT clock 601 is a clock generator at destination terminal 600.

4 shows clock source 1, which is an exemplary clock signal, where pulses are separated by period T ₀ . In this figure, N pulses over a predetermined period of time (eg, one frame) are shown.

5 shows another exemplary clock signal, clock source 2, where the pulses are separated by period T ₁ . In this example, T ₁ is less than T ₀ of clock source 1 (ie, clock source 2 is a higher frequency clock than clock source 1). In that figure, N + 1 pulses are shown over one frame, illustrating the case where there is one additional pulse in the frame compared to clock source 1. This situation is commonly referred to as "sample stuff" or missing samples with additional pulses.

6A shows another exemplary clock signal, clock source 3, where the pulses are separated by period T ₂ . In this example, T ₂ is greater than T ₀ of clock source 1 (ie, clock source 3 is a lower frequency clock than clock source 1). FIG. 6B illustrates a clock “drift” or “skew” situation (ie clock source 3 drifts over time with respect to clock source 1), in which case the frame is divided into clock source 1. It may be present when it is locked with respect to timing but is considered not locked with respect to the timing of clock source 3. 6C illustrates another clock drift situation where N-1 pulses are outside the frame boundary resulting in one less pulse in the frame compared to clock source 1. FIG. Usually this situation is called "missing sample". In an alternative example, clock drift is associated with resampling of the entire signal.

Downlink

7 is an example interaction diagram of a synchronization sequence and a data transmission sequence between a source terminal 100 and a destination terminal 600. The downlink transmission sequence 800 represents the transmission of synchronization and data messages from the destination terminal 600 to the source terminal 100, and the uplink transmission sequence 810 from the source terminal 100 to the destination terminal 600. Represents transmission of synchronous and data messages. In this example, the uplink transmission sequence 810 is initiated by the destination terminal 600. The downlink transmission sequence 800 is initiated at time t0 850 by the destination terminal 600 with the first synchronization sequence 801. A suitable example of the first synchronization sequence 801 includes a synchronous preamble output as shown in FIG. 8A, which results in a correlation peak pattern shown in FIG. 8B. Following the first synchronization sequence 801, the destination terminal 600 transmits a “start” message 802 to instruct the source terminal 100 to begin transmitting the uplink transmission 810 sequence. The destination terminal 600 alternately continues to transmit the first sync 801 and the "start" message 802 and waits for a response from the source terminal 100. At time t1 851, source terminal 100 receiving the " start " message 802 from destination terminal 600 begins to transmit its own synchronization sequence 811. Following the synchronization sequence 811, the source terminal 100 transmits a minimum set of data or “MSD” message 812 to the destination terminal 600. At time t2 852, the destination terminal 600 receiving the synchronization message 811 from the source terminal 100 begins sending a negative acknowledgment or “NACK” message 803 to the source terminal 100. The destination terminal 600 continues to transmit the first sync 801 and the "NACK" message 803 alternately until it successfully receives the MSD message 812 from the source terminal 100. Suitable examples for successfully receiving the MSD message 812 include confirming a cyclic redundancy check performed on the MSD message 812. At time t3 853, the destination terminal 600 successfully receiving the MSD message receives a lower layer acknowledgment or " LLACK signal " consisting of a first sync 801 and a lower layer acknowledgment " LLACK " Start transmitting. At time t5 855, destination terminal 600 begins to transmit a higher layer message or “HLMSG signal” composed of second sync 833 and higher layer message HLMSG 894. A suitable example of the second synchronization signal 893 is an inversion sequence of the sequence shown as 245 (swapped '+' and '-' polarity bits) as shown in FIG. 9A, with the alternating sequence shown in FIG. 9B being alternating. Results in a correlated peak pattern. Source terminal 100 may attempt to send the MSD message 812 813, 814 several times until receiving the LLACK message. In alternative embodiments, source terminal 100 may attempt to send an MSD message 812 several times 813, 814 until it receives an HLMSG message, or both an LLACK message and an HLMSG message. . At time t6 856, source terminal 100 receiving the HLMSG signal from destination terminal 600 stops transmitting the MSD message. In one suitable example, after a predetermined number of HLMSG signals have been sent by the destination terminal 600, retransmission is requested by the destination terminal 600 by sending restart messages 802. In one suitable example, the predetermined number of HLMSG signals sent by the destination terminal 600 is five. In one suitable example, the interaction of FIG. 7 includes an HLMSG signal that includes a second sync 833 and a higher layer message HLMSG 894, but may not contain a LLACK signal (ie, a preceding LLACK signal is present). No HLMSG signal is detected).

motivation sequence -Based synchronous tracking demodulation

Since the sync sequence (preamble) is included with all feedback messages (e.g. START, NACK, LLACK, and HLMSG messages) in the downlink, a check is performed on each of the feedback messages to confirm and track synchronization. May be However, the decision rule should take into account that a synchronization sequence is also used to distinguish higher layer (HL) messages from lower layer (LL) messages. Therefore, ambiguities to the sign of correlation peaks should be avoided. For example, peak search in the neighborhood of the previous location can cause ambiguities between higher layer messages and lower layer messages due to the low pass / band pass characteristics of the transmission channel, and becomes more important with clock drift.

To prevent ambiguities, the reference correlation peak shape may be calculated when synchronization is locked at the downlink receiver. In one suitable example, it is determined which correlation peaks are valid at the time that synchronization is locked. Combining all valid (eg, detected) peaks may determine the reference peak shape. In one suitable example, summing all the valid peaks and scaling the result may determine the reference peak shape. Averaging all valid peaks may also determine the reference peak shape. One exemplary length of the reference peak shape may be five samples, where the actual desired peak is at the center of the peak shape. 10A, 10B, 10C, 10D, and 10E show exemplary correlation peaks for a plurality of peaks. The five peaks shown in FIGS. 10A-10E correspond to five detected peaks from the example preamble shown in FIG. 8A over five samples, where index 0 is the main detected. Represents a peak, and the indices -2, -1, 1, 2 represent respective sample offsets from the largest detected peak. 10A-10E each depict the peak shape of an individual peak, where the actual peak is the correlation value at the center (ie, index 0 in the figures). FIG. 10F shows a reference pulse consisting of a combined set of peaks (eg, scaled sum or average) of FIGS. 10A-10E. Combining peaks (eg, through a scaled sum or averaging) is advantageous, among others, tending to smooth out the fluctuations in which individual peaks may be observed due to distortions caused by the voice channel. Because. In addition, only binding to the detected peaks results in a calculated value, which is not adversely affected by undetected peaks. Therefore, it is advantageous and desirable to perform the binding (eg, scaled sum or averaging) and to perform only the binding on the detected peaks only. A wide range of samples may be tracked using this method, for example a range of [-480, .. + 480] samples may be tracked in the downlink.

11A shows an example flowchart for processing in preparation for sample missing detection. A synchronization signal (eg, 801 or 893) is received at 1110 and correlated with a local reference signal at 1120. If it is determined at 1130 that the synchronization is not locked, then the flow moves back to receiving the synchronization sequence 1110. If the synchronization is determined to be locked, then a reference peak shape is calculated by combining all valid (ie, detected) peaks at 1140.

In one suitable example, the peak may be calculated from the received sync preamble and / or the inverted sync preamble. If both a sync preamble and an inverted sync preamble are detected, a decision is made to determine whether the detected sync is inverted or not inverted using the following decision logic used during the tracking phase:

IF ((number of positive sync peaks> = number of negative sync peaks AND positive peak cross correlation with original pulse shape> negative peak cross correlation with original pulse shape) OR (number of positive sync peaks > Number of negative sync peaks AND Positive peak cross correlation with original pulse shape> Scaled negative peak cross correlation with original pulse shape AND expected to assume that sample missing did not occur Number of negative peaks at the indicated position == 0)) THEN The valid peaks are positive.

ELSE IF ((number of positive sync peaks <= number of negative sync peaks AND positive peak cross correlation with original pulse shape <negative peak cross correlation with original pulse shape) OR (positive sync peaks Count <number of negative sync peaks) AND (scaled (eg, divided by 2) positive peak cross correlation with original pulse shape <negative peak cross correlation AND original sample with pulse shape Assume that the number of positive peaks at the expected position == 0)) THEN The valid peaks are negative.

ELSEIF (the number of positive peaks at the expected position assuming no sample dropout occurred> the number of negative peaks at the expected position assuming no sample dropout occurred) THEN Valid peaks are positive.

ELSEIF (the number of negative peaks at the expected position assuming no sample dropout occurred> the number of positive peaks at the expected position assuming no sample dropout occurred) THEN Valid peaks are negative.

If only one peak is detected then it is considered valid unless there are at least as many peaks detected at the expected position.

In calculating the reference peak shape, valid peaks may be identified according to the following synchronization algorithm. The synchronization algorithm selects a reference peak to detect the presence of any additional peaks at the expected locations; For example, one reference peak and four additional peaks are examined. In one suitable example, the detected peaks are stored as a vector; For example, [01111] will indicate that all peaks except for the first peak have been detected. Depending on how many peaks are in this vector, the synchronization algorithm will continue further tests. In one suitable example, additional tests are based on amplitude values. After further tests, determine whether the synchronization algorithm is a valid synchronization. If all tests are successful; That is, if a synchronous preamble is indicated as detected, then the vector is then combined for those peaks indicated as 1 in the vector (eg, scaled sum or average). In one suitable example, the peaks are combined regardless of the amplitudes of the peaks.

11B shows a flowchart of an example method M100 for processing in preparation for sample missing detection according to the first configuration. Task T1110 receives a synchronization signal (eg, 801 or 893). Task T1120 correlates the received sync signal with a reference signal. Task T1140 calculates a reference peak shape, where the reference peak shape is calculated by combining all valid peaks.

11C shows a block diagram of the apparatus A100. Apparatus A100 comprises means F1110 for receiving a synchronization signal, means F1120 for correlating the received synchronization signal with a reference signal, and means F1140 for calculating a reference peak shape, wherein the reference peak shape Is calculated by combining all valid peaks.

Uplink

Typically, the transmit baseband 200 routes user voice through the vocoder, but it is also possible to route non-voice data through the vocoder in response to a request originating from a source terminal or communication network. Routing non-voice data through the vocoder is advantageous because it eliminates the need for the source terminal to request and transmit data over a separate communication channel. Non-voice data is formatted into messages. Message data, still in digital form, is converted into a noise-like signal consisting of pulses. The message data information is put in the pulse positions and the pulse sign of the noise-like signal. Noise-like signals are encoded by vocoder. Since the vocoder is not configured differently depending on whether the input is user voice or non-voice data, it is advantageous to convert the message data into a signal, which signal can be efficiently encoded by the transmission parameter set assigned by the vocoder. The encoded noise-like signal is transmitted in-band over the communication link. Since the transmitted information is put in the pulse locations of the noise-like signal, reliable detection depends on the recovery of the timing of the pulses for speech codec frame boundaries. To help the receiver detect the in-band transmission, a predetermined sync signal is encoded by the vocoder prior to transmission of the message data. A protocol sequence of synchronization, control, and messages is transmitted to ensure reliable detection and demodulation of non-voice data at the receiver.

12 is one suitable example block diagram of a Tx data modem 230 that may be within the transmit baseband 200 block shown in FIG. 2. The three signals are sent via a multiplexer 259, over time, to a Tx data S230 output signal based on the transmit baseband data S201 in FIG. 2; It may be multiplexed with a sync out (S245), mute out (S240), and a Tx mod out (Sx Mod Out) (S235). It should be appreciated that different orders and combinations of signals, synchronous output S245, mute output S240, and TX modulated output S235 may be output as Tx data S230. For example, sync output S245 may be sent prior to each Tx modulated output S235 data segment. Alternatively, the synchronization output S245 may be sent once prior to the complete Tx modulation output S235 with the mute output S240 sent between each Tx modulation output S235 data segment. In FIG. 12, formatted output data S220 may be based on input data S200.

motivation sequence -Based synchronous tracking modulation

Referring back to FIG. 7, the TxMSD Original Message 812, the TxMSD Attempt 1 813, and the TxMSD Attempt 2 814 may all be based on the Tx data S230. have. Additional TxMSD attempts may be sent (eg, attempt 3). Each TxMSD attempt may include additional mute and sync messages and may be referred to as a redundancy version, where each try, mute, and sync corresponds to a different duplicate version. One suitable example of supporting uplink sync tracking is through the insertion of additional reference pulses during muting periods. This leaves the modulation frames unchanged, but extends the overall length of each redundant version. A complex set of mute, sync, and Tx modulated data defining three exemplary redundant versions is shown in FIG. 13. Twu1 701, Tsp1 702, and Td1 703 represent periods in terms of frames in which each signal is transmitted in a first redundant version. One suitable example for Twu1 is two frames, four frames for Tsp1 and 15 frames for Td1. Twu2 711, Tsp2 712, and Td2 713 represent periods in terms of frames in which each signal is transmitted in a second redundant version. One suitable example for Twu2 is four frames, four frames for Tsp2 and 16 frames for Td2. Twu3 721, Tsp3 722, and Td3 723 represent periods in terms of frames in which each signal is transmitted in a third redundant version. One suitable example for Twu3 is two frames, four frames for Tsp3 and 16 frames for Td3. A preferred alternative to FIG. 7, which is an uplink transmission protocol, is shown in FIG. 14A, including the composite sync, mute, and data shown in FIG. 13. Alternatively, FIGS. 14B and 14C show different configurations of mute and sync signals (eg, mute prior to sync, or mute / sync / mute sequence). Compound mute, sync, and data provide an advantage by enabling more robust detection and tracking of sample miss situations. In FIGS. 14A-14C, the TxMSD original message 812, the TxMSD attempt 1 813, and the TxMSD attempt 2 814 may all be based on the Tx data S230. The difference between the uplink transmissions of FIGS. 7 and 14A-14C is that mutes 815a and 815b and syncs 816a and 816b are sent with TxMSD attempts to form redundant versions.

15 shows one suitable example of sparse pulses that may be used to transmit data using a pulse position modulation (PPM) based technique. The time axis is divided by the period T _MF of modulation frames. Within each such modulation frame, the number of time instances (t ₀ , t ₁ ,..., T _{m -1} ) is defined relative to the modulation frame boundary, which is the fundamental pulse p ( Identify potential locations in t). For example, pulse 237 at position t ₃ is represented by p (t − t ₃ ). The formatted input data (S220) information bits input to the modulator 235 are mapped to symbols having a corresponding interpretation of the pulse positions according to the mapping table. The pulse may also be shaped with polarity switching ± p (t). Therefore, the symbols may be represented by one of the 2m distinct signals in the modulation frames, where m represents the number of viewpoints defined for the modulation frame, and the multiplication factor 2 represents a positive polarity and Representation of negative polarity.

An example of suitable pulse position mapping is shown in Table 1. In this example, the modulator maps 3-bit symbols per module frame. Each symbol is represented in terms of the position k of the pulse shape p (nk) and the sign of the pulse. In this example, there are 16 possible shifts for the original transmit pulse in the modulation frame of 16 samples in length. Based on an example of sixteen possible shifts, Table 1 defines four possible PPM locations separated by each of a predetermined number of viewpoints. In this example, the initial offset is set to one time point, and the pulses are separated into four time points, respectively, causing shifts of 1, 5, 9, and 13 time points. A total of eight different pulse positions and polarity combinations are mapped to the symbols.

symbol

pulse Decimal binary scale 0 000 p (n-1) One 001 p (n-5) 2 010 p (n-9) 3 011 p (n-13) 4 100 -p (n-13) 5 101 -p (n-9) 6 110 -p (n-5) 7 111 -p (n-1)

Modulation-based synchronous tracking modulation

The modulation throughput may be reduced for each modulation frame by using unipolar PPM instead of bipolar PPM. This provides an advantage in compensating for sample missing situations, since if the sync tracking is based on modulation pulses instead of additional sync sequences, the sign bit is now free to be used for sync tracking. In one suitable example, the PPM symbol mapping is reduced from 3 bits to 2 bits by removing the sign bit as shown in Table 2.

symbol

pulse Decimal binary scale 0 00 p (n-1) One 01 p (n-5) 2 10 p (n-9) 3 11 p (n-13)

To compensate for throughput reduction when using unipolar PPM, a mixed mode frame format consisting of regular modulation frames (ie, data frames) and sync tracking modulation frames may be used. In one suitable example, a 2/3 bit mixed mode frame format may be implemented, where regular 3 bit modulation frames and 2 bit tracking modulation frames alternate in a single vocoder frame. In one suitable example, the modulator may use 9 modulation frames per vocoder frame with payload pattern 3/2/3/2/3/2/3/2/3 bits = 23 bits per vocoder frame. To further illustrate bit breakdown, 5 × 16 samples / symbols for 3 bit modulation plus 4 × 20 samples / symbols for 2 bit modulation is 160 samples / frame.

Depending on throughput requirements, either a strong or fast modulator may be used. In one suitable example, the powerful modulator uses five modulation frames per vocoder frame with payload pattern 2/3/2/3/2 bits = 12 bits per vocoder frame.

With the code bits available in the case of the unipolar PPM technique, the pulses may be modulated by the PN-sequence to provide sign randomness. Suitable examples for PN-sequences may include, but are not limited to, length 15 PN-sequences as described herein, or additional Gold sequences with increased period lengths. Gold sequences are well known in the art. Two suitable examples for associating a PN-bit with four pulse positions in each modulation frame may be implemented.

In a first suitable example, one bit of the PN-sequence may be mapped to the last pulse, regardless of the actual pulse position in the modulation frame. In one suitable example, a length-15 PN sequence may be used as described at 242 of FIG. 8A, where '+' symbols represent a + 1 and '-' symbols represent a − 1. The PN-sequence of 242 along with the bit index is shown in Table 3.

PN
pattern +1 +1 +1 +1 -One +1 -One +1 +1 -One -One +1 -One -One -One Bit index 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14

The index count tracks the modulation frames and is based on duplicate versions, the number of frames per duplicate version, the number of data frames, and the number of tracking modulation frames. For example, a mixed mode configuration with 60 data frames per redundant version (plus 12 muting frames) and 9 modulation frames per frame, 4 of which consider tracking modulation frames. For example, if the uplink modulator state was in duplicate version 2, data frame 35 in the duplicate version, and tracking modulation frame 3 in the data frame (assuming all counts start at zero), the tracking index is: index = (2 * 60 + 35) * 4 + 3 = 623. The modulo of the PN sequence length is taken at the index, which gives the bit index within the PN pattern. For index 623 and PN length 15, the bit index is 8 (ie 623% 15 = 8). The last transmit pulse is then weighted by the PN-bit code according to the bit index, which in this example is +1 weighted according to bit index 8 (see Table 3 for bit index mapping for the PN bit pattern).

In a second suitable example, each pulse location within a modulation frame may be assigned a specific PN-sequence. This example illustrates boundary misses of one or more samples (eg, ± 3 samples in sample interval 5) by cyclically shifting the original PN-sequence and inverting the sign to cover a set of possible pulse positions. It may also improve the robustness to location ambiguities in. This example may resolve offset ambiguities in the boundary offset of the tracking range. In this example, each PPM location has its individual PN pattern, and the PN bit code not only depends on the bit index, but also on the actual two bit data depending on the PPM location in the tracking modulation frame. In one suitable example, consider the pattern array used for a length-15 PN sequence (pattern positions 1 to 3 due to cyclic shift and sign inversion of pattern position 0) as shown in Table 4:

PN
pattern
Position 0 +1 +1 +1 +1 -One +1 -One +1 +1 -One -One +1 -One -One -One PN
pattern
Position 1 +1 -One +1 -One -One +1 +1 -One +1 +1 +1 -One -One -One -One PN
pattern
Position 2 +1 -One -One +1 -One -One -One +1 +1 +1 +1 -One +1 -One +1 PN
pattern
Position 3 +1 +1 +1 -One -One -One -One +1 -One +1 -One -One +1 +1 -One beat
index 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14

In Table 4, the four positions are associated with a two bit example pulse as shown in Table 2. The PN pattern for position 0 is a length-15 PN sequence as described at 242, where the '+' symbol represents a + 1 and the '-' symbol represents a −1. The PN pattern for position 1 is the position 0 pattern inverted after being shifted left by 4 bits. The PN pattern for position 2 is a position 0 pattern shifted left by eight. The PN pattern for position 3 is the position 0 pattern inverted after being shifted left by 12 bits. Then, as in the previous example, if the bit index for PPM position 3 was 8, for example, the PN-bit code is -1, which, in turn, defines the weight of the transmit pulse corresponding to PPN position 3. do.

The pulses shown in FIG. 15 may be further shaped according to the shape function. A good example of a shape function is

It is a form of root-raised cosine transform. Where β is a roll-off factor, 1 / T _s is the maximum symbol rate, and t is the sampling point. It should be appreciated that the transition may be shorter or longer for different variations of modulation frame sizes.

In one suitable example, the transmit pulse may be adjusted for improved location estimation, which may be achieved by setting one or more samples that surround the pulse maximum at zero. In one suitable example, pulses near the maximum in the root-rise cosine transform are set to zero.

Range [-M,. To prevent potential detection ambiguities. . . , PPM interval may be extended with sample offsets within + M]. In one suitable example, the PPM interval may be increased from 4 samples to 5 samples. In one suitable example, the modulation frame is 20 samples long, and one vocoder frame contains 8 modulation frames (instead of 10 modulation frames as in the original PPM interval).

Modulation-based synchronous tracking demodulation

To detect the sample offset, the demodulator may calculate the pulse correlation for all possible sample offsets within the target range [-N, .. + N]. This target range may correspond to calculating a PPM interval divided by two and taking the smallest integer that is greater than the result (ie, the "ceiling" function of mathematics). In one suitable example with sample interval 5, the target range is [-3, .. +3]. The demodulator may use a matched filter that matches the pulse shape. A diagram of one suitable example of a sample missing detector is shown in FIG. 16A. The correlation is calculated at 1610. Next, at 1620 a relative decision metric is determined. Decision metrics are advantageous in that they maximize detection rates and minimize the possibility of false alarms. The relative metric is represented by the maximum correlation of all possible offsets determined for the correlation value at zero offset, where the zero offset represents the absence of omission. Next, at 1630 the relative metric is compared against a threshold for M consecutive frames. One suitable example for M is 40-50 modulation frames. If the relative metric is greater than the threshold T for M consecutive frames, then a sample miss is declared at 1640, otherwise the detector terminates or repeats the search. The sample missing declaration at 1640 indicates that the correlation was moved off the zero offset and that a missing occurred. In one alternative embodiment, the relative metrics determined for the current frame and the next frames are compared so that if they fall within a predetermined range of each other, then a sample miss is declared. In one suitable example, a plurality of decision differences are calculated, where the decision difference is based on comparing the maximum correlation of all possible offsets in the frame against the correlation at zero offset. If the decision differences fall within a predetermined range, then a sample missing situation is declared. In one alternative embodiment, relative metrics determined for the current frame and the next frames are compared and ignored if they fall outside the predetermined range.

16D shows a flowchart for a method M200 of an exemplary sample missing detector according to the first configuration. Task T1610 calculates the correlation. Task T1620 determines the relative decision metric. Task T1640 determines whether sample dropout has occurred by comparing the relative metric against a threshold for M consecutive frames.

16E shows a block diagram of apparatus A200. Apparatus A200 includes means for calculating correlation F1610, means for determining relative determination metric F1620, and means for determining whether sample dropout has occurred by comparing the relative metric against a threshold for M consecutive frames. (F1640).

One problem in finding the correlation maximum among all possible sample offsets is that the PPM position selected at the transmitter is not known apriori to the receiver side. Two appropriate examples solve the problem of finding a correlation. In a first suitable example for calculating a correlation (1610), a two stage search is performed to determine the most likely pulse position and sample offset, where the first stage is a plurality of pulse positions for each offset. Determine a correlation maximum, and the second stage finds the correlation maximum among all possible offsets in the target range around the correlation maximums of the first stage. A diagram of a two stage search is shown in FIG. 16B. In step 1660 an approximate search is performed, where the maximum correlation among the N pulses in the frame is found. One suitable example for N is 4. Next, a detailed search is performed in step 1670, where a vector of possible correlation maxima is computed, one maximum for each of the sample offsets within the tracking range. This step is performed among N possible PPM positions for a given offset. In one suitable example, if the tracking range was [-3 ... +3], then this step would provide seven possible correlation maximums. Next, a global correlation maximum is identified in the vectors of possible correlation maximums. Then, the associated sample offset is input into the missing detection logic.

In a second suitable example for calculating a correlation (1610), to form a single “comb” reference pulse that allows all matched filter pulses (which are cyclically shifted versions of the original pulse) to enable the calculation of correlations. It may also be superimposed. A diagram of a comb pulse based search is shown in FIG. 16C. Correlation is calculated 1650 for all possible offsets within the target range for this comb pulse. One suitable example for the target range is [-3, .. +3], which corresponds to a sampling interval of at least five. A diagram of one exemplary comb pulse, for a two bit (four position) pulse, is shown in FIG. 17A. Comb-matched filter pulses are formed by superimposing these four matched-filter pulses. In one suitable example, the pulses include PN-bit codes according to PN pattern tables (eg, Table 3 or Table 4). This means that for a length-15 PN sequence, there are 15 different comb matched-filter pulses corresponding to PN-bit indexes 0-14. For example, FIG. 17A represents the comb pulses for the bit 0 index (position 0..position 4) of Table 4, where pulse 1701 represents position 0, 1702 represents position 1, and 1703 represents Represents position 2 and 1704 represents position 3. Similarly, FIG. 17B represents the comb pulses for bit index 1 in Table 4, where pulse 1711 represents position 0, 1712 represents position 1, 1713 represents position 2, and 1714 represents position Express 3 The complete mapping of the bit indices to generate the comb pulses for Table 4 is shown in FIGS. 18A (bit indexes 0-7) and 18B (bit indexes 8-14).

FIG. 19A shows a block diagram of one implementation of apparatus A100 (ie, sync sequence-based sync tracking algorithm) and A200 (ie, modulation-based sync tracking algorithm) according to a second configuration. The processor 1900 is in communication with a memory 1920, a transmitter 295, and a receiver 495. The memory 1920, when executed by the processor 1900, receives a sync signal, correlates the received sync signal with a reference signal, determines if sync is locked, and combines all valid peaks to form a reference peak shape. And instructions 1925 and data 1922 for executing the synchronization sequence-based synchronization tracking algorithm. In the alternative, the processor 1900 communicates with a memory 1920, a transmitter 295, and a receiver 495, where the memory 1920, when executed by the processor 1900, is a two-step approximation. Calculate correlation by search and detailed search process, calculate correlation by correlating all possible offsets with reference comb pulse, determine relative decision metric by calculating maximum correlation of all possible offsets to correlation at zero offset Additional data 1922 and instructions 1925 to execute a modulation-based sync tracing algorithm to determine if the relative decision metric is greater than the metric for the M consecutive frames, thereby determining that a sample miss occurs. Include.

19B shows a block diagram of one implementation of apparatus A100 (ie, sync sequence-based sync tracking algorithm) and A200 (ie, modulation-substrate sync tracking algorithm) according to a third configuration. The processor 1900 is in communication with a memory 1920, a transmitter 295, and a receiver 495. The memory 1920, when executed by the processor 1900, receives a synchronization signal as described herein in connection with an implementation of task T1110 and means F1110 and converts the received synchronization signal into an implementation of task T1120 and means F1120. To generate a reference peak shape by correlating with a reference signal as described herein in connection with this, and combining all valid peaks as described herein in connection with the implementation of task T1140 and means F1140. It contains tasks that run the tracking algorithm. In the alternative, the processor 1900 communicates with a memory 1920, a transmitter 295, and a receiver 495, where the memory 1920, when executed by the processor 1900, is a two-step approximation. The correlation is calculated by a search and detailed retrieval process, and the correlation is calculated by correlating all possible offsets with respect to the reference comb pulse as described herein in connection with the implementation of tasks T1610 and means F1610, Determine a relative decision metric by calculating a maximum correlation of all possible offsets for a correlation at zero offset as described herein with respect to the implementation, and relative as described herein with respect to the implementation of tasks T1640 and means F1640. Modulation-based sync tracking algorithm to determine if the decision metric is greater than the metric for M consecutive frames Includes additional tasks to execute the program. Those skilled in the art will appreciate that subsets of tasks may exist in memory 1920.

In general, the methods and apparatuses described herein may be applied to any transmit and receive and / or audio sensing application, in particular for the mobile or otherwise portable case of such applications. For example, the scope of the configurations described herein includes communication devices in a wireless telephony communication system configured to use code-division multiple-access (CDMA) over the air-interface. However, a method and apparatus having the features as described herein may be used to provide Internet telephony protocol (VoIP) over wired and / or wireless (eg, CDMA, TDMA, FDMA, and / or TD-SCDMA) transmission channels. It will be understood by those skilled in the art that the system may be within any of a variety of communication systems using a wide range of techniques known to those skilled in the art, such as the systems used.

The foregoing description of the described configurations is provided to enable any person skilled in the art to make or use the methods and other structures disclosed herein. The flowcharts, block diagrams, and other structures shown and described herein are merely examples, and other variations of such structures are also within the scope of this disclosure. Various modifications to these configurations are possible, and the general principles presented herein may be applied to other configurations as well. Therefore, the present disclosure is not intended to be limited to the configurations shown above, but includes the appended claims as set forth herein, which form part of the original disclosure, as well as the principles and novel features disclosed in any manner herein. I would like to meet the widest range that matches them.

Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, instructions, information, signals, bits, and symbols that may be referenced throughout the description may include voltages, currents, electromagnetic wavelengths, magnetic fields or particles, light. It may be represented by fields or particles, or any combination thereof.

Various elements of the implementation of the apparatus as described herein may be included in any combination of hardware, software, and / or firmware deemed appropriate for the intended applications. For example, such devices may be fabricated with electronic and / or optical devices, for example, between two or more chips on the same chip or chipset. One example of such a device is a fixed array or programmable array of logic elements, such as transistors or logic gates, any of which may be implemented as one or more such arrays. Any two or more, or even all, of such devices may be implemented in the same array or arrays. Such an array or arrays may be implemented in one or more chips (eg, in a chipset including two or more chips).

In addition, one or more elements of the various implementations of the devices disclosed herein may be microprocessors, embedded processors, IP cores, digital signal processors, field-programmable gate arrays (FPGAs), custom standard As one or more sets of instructions provided for execution on one or more fixed arrays or programmable arrays of logic elements, such as application-specific standard products (ASSPs), and application-specific integrated circuits (ASICs) It may be implemented in whole or in part. In addition, any of the various elements of the implementation of the devices as described herein may be programmed to execute one or more sets or sequences of instructions, also referred to as one or more computers (eg, “processes”). Machines including one or more arrays), and any two or more, or even all of these elements may be implemented within the same such computer or computer programs.

A processor or other means for processing as described herein may be fabricated as one or more electronic and / or optical devices, for example, between two or more chips in the same chip or chipset. One example of such a device is a fixed array or programmable array of logic elements, such as transistors or logic gates, any of which may be implemented as one or more such arrays. Such an array or arrays may be implemented in one or more chips (eg, in a chipset including two or more chips). Examples of such arrays include a fixed array or programmable array of logic elements such as microprocessors, embedded processors, IP cores, DSPs, FPGAs, ASSPs, and ASICs. In addition, a processor or other means for processing as described herein may be one or more computers (eg, machines that include one or more arrays programmed to execute one or more sets or sequences of instructions), or It may be included as other processors. A task as described herein is used to perform tasks or perform other sets of instructions not directly related to higher protocol messaging procedures, such as tasks relating to other operations of the device or system in which the processor is embedded. It is possible. In addition, it is possible that one part of the method as described herein is performed by the first processor, and the other part of the method is performed under the control of one or more other processors.

Those skilled in the art will appreciate that the various illustrative modules, logic blocks, circuits, and tests and other operations described in connection with the configurations disclosed herein may be implemented in electronic hardware, computer software, or a combination of both. Will understand. Such modules, logical blocks, circuits, and operations may be used in general purpose processors, digital signal processors (DSPs), ASICs or ASSPs, FPGAs or other programmable logic devices, separate gate or transistor logic, separate hardware components, or herein. It may be implemented or performed with any combination of those designed to produce a configuration as disclosed. For example, such a configuration may be, at least in part, logic such as a hard-wired circuit, a circuit configuration built on demand integrated circuits, or a firmware program loaded into non-volatile storage, or a general purpose processor or other digital signal processing unit. It may be implemented as a software program loaded into or from a data storage medium, such as machine-readable code, instructions that are executable by an array of elements. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, eg, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors with a DSP core, or any other such configuration. Software modules may include random-access memory (RAM), read-only memory (ROM), nonvolatile RAM (NVRAM) such as flash RAM, erasable programmable ROM (EPROM), electrical May be in erasable programmable ROM (EEPROM), registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An example storage medium is coupled to the processor such that the processor may read information from and write information to the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may be in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

One exemplary control device is coupled to the control system. Included in the control system are modules for instructing the control system to perform the operations described in connection with the configurations disclosed herein. The modules may be implemented as indication modules encoded into the control device. The control device includes random-access memory (RAM), read-only memory (ROM), nonvolatile RAM (NVRAM) such as flash RAM, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), Registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

It should be noted that the various methods disclosed herein may be performed with an array of logic elements, such as a processor, and the various elements of the apparatus as described herein may be implemented as modules designed to run on such an array. As used herein, the term “module” or “sub-module” refers to computer instructions (eg, logical representations) in the form of any method, apparatus, device, unit, or software, hardware, or firmware. And may be associated with a computer-readable data storage medium. It will be appreciated that multiple modules or systems may be combined into one module or system, and one module or system may be separated into multiple modules or systems, to perform the same functions. When implemented in software or other computer-executable instructions, the elements of a process are basically code segments for performing related tasks such as routines, programs, objects, components, data structures, and the like. The term "software" means any one or more sets or sequences of instructions that may be executed by source code, assembly language code, machine code, binary code, firmware, macrocode, microcode, arrays of logical elements, and such examples. It will be understood to include any combination of these. The program or code segments may be stored in a processor readable medium or transmitted by a computer data signal included in a carrier via a transmission medium or communication link.

Implementations of the methods, techniques, and techniques disclosed herein are readable and / or executable by a machine (eg, a processor, microprocessor, microcontroller, or other finite state machine) that includes an array of logic elements. One or more sets of instructions may be included in the type (eg, in one or more computer-readable media as listed herein). The term “computer-readable medium” may include any medium capable of storing or transmitting information, including volatile, nonvolatile, erasable, and non-erasable media. Examples of computer-readable media include electronic circuitry, semiconductor memory devices, ROMs, flash memory, erasable ROM (EROM), floppy diskettes or magnetic storage, CD-ROM / DVD or other optical storage, hard disks, optical fiber media, Radio frequency (RF) links, or any other medium that can be used and accessed to store desired information. The computer data signal may include any signals capable of propagating through transmission media such as electronic network channels, optical fibers, air, electromagnetics, RF links, and the like. Code segments may be downloaded via computer networks such as the Internet or an intranet. In any case, the scope of the present disclosure should not be construed as limited to such embodiments.

Each of the tasks of the methods described herein may be directly included in hardware, a software module executed by a processor, or a combination of the two. In a general application of the implementation of a method as disclosed herein, an array of logic elements (eg, logic gates) is configured to perform one, one or more, or even all of the various tasks of the method. In addition, one or more (possibly all) of the tasks may comprise an array of logic elements (eg, a processor, a microprocessor, a microcontroller, or other finite state machine) to a machine (eg, a computer). Code (eg, instructions contained in a computer program product (e.g., one or more data storage media such as disks, flash memory card or other nonvolatile memory card, semiconductor memory chip, etc.) executable and / or executable by May be implemented as one or more sets). In addition, tasks of implementation of a method as disclosed herein may be performed by one or more such arrays or machines. In such or other implementations, the tasks may be performed within a device for wireless communication, such as a cellular telephone or other device having such communication capabilities. Such a device may be configured to communicate with a circuit-switched network and / or a packet-switched network (eg, using one or more protocols such as VoIP).

The various methods disclosed herein may be performed by portable communication devices such as a handset, headset, or portable digital assistant (PDA), and the various apparatuses described herein may clearly be included within such a device. do. A typical real time (eg, online) application is a telephone call made using such a mobile device.

In one or more illustrative embodiments, the operations described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, such operations may be stored or transmitted over as one or more instructions or code on a computer-readable medium. The term “computer-readable media” includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may include semiconductor memory (which may include, but are not limited to, dynamic or static RAM, ROM, EEPROM, and / or flash RAM), or ferroelectric, magnetoresistive And may be used to carry or store desired program code in the form of polymerization, or phase-change memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or instructions or data structures. It can include an array of storage elements, such as any other medium that can be accessed by a computer. In addition, any connection is properly termed a computer-readable medium. For example, if the software is a website, server, or other using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, wireless, and / or microwave When transmitted from a remote source, then wireless technologies such as coaxial cable, fiber optic cable, twisted pair, DSL, or infrared, wireless, and / or microwave are included within the definition of the medium. Discs and discs as used herein include compact discs (CDs), laser discs, optical discs, digital volatile discs (DVD), floppy discs, and Blu-ray DiscsTM (California Universal City, Blu-Ray Disc Association, where disks usually reproduce data magnetically, while disks use lasers to optically reproduce data. Combinations of the above should also be included within the scope of computer-readable media.

Claims (15)

Receiving a synchronization sequence, the synchronization sequence comprising at least a repeating pseudorandom sequence;
Correlating the received synchronization sequence with a reference signal;
If synchronization is locked at the receiver, calculating a plurality of correlation peaks based on the repeating pseudorandom sequence; And
Identifying a sample slip in the transmission channel of the in-band modem based on the correlation peaks. The method of claim 1,
Calculating a correlation peak shape, wherein calculating the correlation peak shape comprises combining the peaks. The method of claim 2,
And wherein said combining comprises combining. The method of claim 1, wherein the combining comprises combining. The method of claim 2,
The calculating step further includes determining which correlation peaks are valid, and wherein combining further includes adding at least only valid peaks to identify a sample missing in a transmission channel of the in-band modem. How to. A receiver for receiving a synchronization sequence, the receiver receiving the synchronization sequence, the synchronization sequence comprising at least a repeating pseudorandom sequence;
A correlator for correlating the received synchronization sequence with a reference signal; And
If synchronization is locked at the receiver, the processor comprising a processor that calculates a plurality of correlation peaks based on the repeating pseudorandom sequence and identifies a sample slip based on the correlation peaks An apparatus for identifying a sample missing in the transmission channel of my modem. The method of claim 5, wherein
And the processor further performs calculating a correlation peak shape, and calculating the correlation peak shape comprises combining the peaks. The method according to claim 6,
And said combining includes combining. The apparatus of claim 2, wherein the combining comprises combining. The method according to claim 6,
And the calculating further comprises determining which correlation peaks are valid, and wherein combining further includes adding at least only valid peaks. Means for receiving a synchronization sequence, the synchronization sequence comprising at least a repeating pseudorandom sequence;
Means for correlating the received synchronization sequence with a reference signal;
Means for calculating a plurality of correlation peaks based on the repeating pseudorandom sequence if synchronization is locked at the receiver; And
Means for identifying a sample slip based on the correlation peaks. The method of claim 9,
Means for calculating a correlation peak shape, wherein the means for calculating a correlation peak shape comprises means for combining the peaks. 11. The method of claim 10,
And the means for combining comprises means for combining. The apparatus for identifying a sample miss in a transmission channel of an in-band modem. 11. The method of claim 10,
The means for calculating further comprises means for determining which correlation peaks are valid, and the means for combining further comprises means for summing at least only valid peaks. Device for Memory that stores computer programs,
The computer program, when executed, causes the computer to:
Receiving a synchronization sequence, the synchronization sequence comprising at least a repeating pseudorandom sequence;
Correlating the received synchronization sequence with a reference signal;
If synchronization is locked at the receiver, calculating a plurality of correlation peaks based on the repeating pseudorandom sequence; And
And perform a step of identifying a sample slip based on the correlation peaks. The method of claim 13,
When executed, further comprising a computer program for causing the computer to perform an operation of calculating a correlation peak shape, wherein the operation of calculating the correlation peak shape comprises combining the peaks. Memory. The method of claim 13,
When executed, further comprising a computer program for causing the computer to perform an operation of determining which correlation peaks are valid, and the combining operation further includes an operation of combining at least only valid peaks. Memory.

Images